In the past, a drum washing machine rotates a transverse-shaft type drum in an outer drum which stores water at a bottom, washings are lifted up and dropped down by baffles arranged in the drum, and the washings are thrown to an inner circumferential surface of the drum to wash the washings (with reference to patent literature 1).
In this way, in a structure of stirring the washings by the baffles, the washings are difficult to twine or rub against each other. Therefore, compared with an automatic washing machine which washes the washings through rotation of a pulsator in a washing and dewatering drum, the drum washing machine has mechanical force, acting on the washings, easy to get small, and has washing performance easy to lower.
Therefore, for the drum washing machine, in order to improve the washing performance, the following structure may be adopted: a heater is configured in the outer drum and water stored in the outer drum is heated through the heater.
Under a condition of adopting the structure that the water in the outer drum is heated through the heater, power consumption required for washing operation is easy to increase.